The invention concerns a packaging machine having a transfer device for inserting a product into a package, and with a circulating leaflet supply device comprising a plurality of tong-like holders which are disposed in a row, each for receiving one leaflet, the leaflet supply device disposing the leaflet in the region of the transfer device between the product and the package such that the leaflet can be inserted together with the product into the package, wherein an opening unit, comprising several stops which can be actuated separately, is disposed in the transport path of the holders to open the holders for releasing the leaflet, wherein the stops can be brought into a non-operative position in which the holder passes the stops without releasing the leaflet.
A packaging machine of this type usually has a first circulating supply device for the package, e.g. a so-called folded box chain, and a second circulating supply device for the products, e.g. a so-called product chain. The motions of these two chains are synchronized such that the product can be laterally inserted into the folded box by an insertion plunger, transversely to the direction of motion of the chains. For certain products, e.g. medication, an additional leaflet or side note must be inserted into the package. For this reason, one further circulating supply device is provided which supports several tong-like holders each of which can receive and clamp one leaflet. A leaflet to be inserted into the package is positioned in the supply device between the product and the folded box and is carried along by the product through its lateral inserting motion to be inserted into the folded box. As soon as the product abuts the leaflet, the tong-like holder must be opened to release the leaflet. Towards this end, an opening unit is provided in the region of the transfer device, e.g. in the form of a stop or opening wedge, against which the tong-like holder abuts during its supply motion thereby opening the tong arms and releasing the leaflet.
Small irregularities may occur during operation of the packaging machine. The folded boxes may thereby be supplied to the folded box chain or the products supplied to the product chain in a discontinuous fashion such that either one or more sections of the folded box chain have no folded box or one or more sections of the product chain contain no product. A sensor detects when a folded box or a product is missing such that the insertion plunger is not activated and no product is inserted.
In older packaging machines, the stop is rigidly installed and the tong-like holder also opens when no product is being inserted into a folded box. It has turned out that the leaflet released in this case, can move randomly through the packaging machine and cause malfunction as well as temporary stoppage, which requires time-consuming and expensive manual intervention. To solve this problem, DE 199 18 527 A1 proposes bringing the opening wedge out of the transport path of the tong-like holder into an inoperative position, when required. In this fashion, the tong-like holder opens and releases the leaflet only when a folded box is actually present in the folded box chain and the product chain contains a product. When no folded box or no product is present, the opening wedge is removed from the transport path of the tong-like holders such that the tong-like holder with leaflet passes the stop and is not opened thereby. The stop then returns into its operative position to open the next tong-like holder if the conditions required therefor are met.
In a modern packaging machine, the amount of time required for one working cycle is only a few milliseconds. During this time, the conditions required for adjusting the stop, at least with regard to the product and the package, must be detected and evaluated and the operating means must be activated to adjust the stop. To ensure safe removal of the leaflet from the tong-like holder during insertion of the product, the tong-like holder must be kept open by the stop for a sufficient period of time. This required period of time is usually longer than the working cycle of a rapidly working packaging machine. In this case, DE 199 18 527 A1 proposes a stop consisting of several stop elements disposed one behind the other in the transport direction of the tong-like holders, which can be adjusted independently of each other between the operative position and the inoperative position. The size of each stop element in the transport direction of the tong-like holders is thereby smaller than the mutual separation between successive holders such that each stop element can return to its operative position as soon as a holder which cannot be opened has passed it and before the next holder comes into the region of the stop element. It has turned out that, when the packaging machine works rapidly, the cycling times, i.e. the time between passage of successive tong-like holders and therefore successive leaflets, is too short to come to a decision concerning the opening or not opening of the tongs and to adjust the stops or the stop elements accordingly as well as to carry out the adjustment motion of the stops with sufficient precision when required.
It is the underlying purpose of the present invention to provide a packaging machine of the mentioned type with which sufficient time is provided for a precise adjustment motion of the stops.